p/df: also ignore devtmpfs

devtmpfs should be excluded by default also.

I explicitly don't exclude tmpfs as it is quite useful as metric.

Closes: D:710899
Merge branch 'fix/d/710899' into stable-2.0
Remove typo in the example rrdcached socket documentation
plugins/df_abs: fix the multiple block device

The special devices like tmpfs or none can appear multiple times,
so we need to append the mount point.

Closes: D#712793
Merge branch 'fix/d/712793' into stable-2.0
gitignore: ignoring output dir sandbox/
Merge pull request #116 from steveschnepp/ignore-sandbox

gitignore: ignoring output dir sandbox/

Conflicts:
	.gitignore
master: fix "graph_period hour"

The "graph_period hour" setting does not work as expected, it stays "second".

Closes: #1305
Merge branch 'fix/1305-graph-period-hour-not-working' into stable-2.0
plugins: fix uninitialized $MUNIN::VERSION

Commit 733f01b1ad48c1e59f0804318a90615429f68e77 introduced a
specific user agent for munin plugins.

But it forgot to import the Munin::Plugin package.

Closes: D:717265
Merge branch 'fix/d/717265-use-uninit-val-const' into stable-2.0

Conflicts:
	plugins/node.d/nginx_request.in
	plugins/node.d/nginx_status.in
2.0.17
Set initial permission of logfiles without executable

As reported in #717847
Don't remove a directory the package don't ownes.

The directory /var/lib/munin-node/ is part of munin-plugins-core but it was
removed by munin-node's postrm. In a situation where munin-node is purged and
re-installed but munin-plugins-core is not the directory will not be recreated.
Some plugins stop working because of missing STATEDIR.
Really remove munin config snippet from apache2/conf.d/

We tested if a file exists but the symlink was already broken. So the dangling
symlink was untouched. Now we check for a symlink and remove them.
Merge tag '2.0.17' into debian

2.0.17
release as 2.0.17-1 to Debian sid